Hi Stefaan,
Hmm... I know you said you used the media creation tool to create either a usb install?
The trouble is sometimes this tool doesn't work properly creating a bootable usb drive and I just wonder if your copy of windows is slightly corrupt.
Your better off downloading the disk image iso and then using something like
Rufus to create the bootable usb.
You then boot from the actual usb by changing the boot order via the bios, did you do this when you installed windows?